1. Field of the Invention
The invention disclosed in this specification is a voltage measuring device for use with a high voltage alternating current power line.
2. Description of the Prior Art
When it is desired to measure the voltage in a power line carrying several thousand volts two types of devices are currently in widespread general use. One is the potential transformer and the other is the capacitor coupled voltage transformer (CCVT). Generally, it can be said that the CCVT replaces the potential transformer because of its much lower cost. Both units require direct connections to the bus or high voltage line and both are large pieces of equipment requiring crews of men to install, replace, or transport them for test purposes.
My invention is quite different from both of these measuring devices. It not only is a fraction of the original cost, weighs a fraction of the weight of either of these devices, but also requires much less labor and time to set up, service, test, or maintain it.
Of the known prior patent art, the closest reference is that of H. W. Ecker et al bearing U.S. Pat. No. 2,927,269. Basically, this reference discloses the use of a capacitive-resistive with a low voltage low current indicator. One of the test electrodes is radioactive and in a probe with the spacing between this probe and the test surface or bus line forming a capacitor without actually contacting the line. My invention is similar, however, it differs in that it overcomes the required discharge needed in the Ecker invention (see column 1, lines 17-55), does not require a radioactive electrode in the probe to work, and contemplates operating in the capacitive mode. Other advantages or differences over Ecker are that my invention will readily measure a.c., but will not be satisfactory for d.c. measurements as in Ecker.